Background:
Folic acid (pteroylglutamic acid, FA), known as a water soluble vitamin of B complex family,
plays an important role in the human body. However, excess intake of FA would mask the vitamin B12 deficiency
symptoms which may lead to other health risks. Therefore, it is very important to develop a method for the sensitive and
selective determination of FA in natural sources, fortified foods and multivitamin preparations.
Methods:
An electrochemical sensor was fabricated for the analysis of FA, which was based on electropolymerized
molecularly imprinted poly (o-aminophenol) film and reduced graphene oxide decorated with Au nanoparticles
composites (rGO-AuNPs). Transmission electron microscope, cyclic voltammetry, electrochemical impedance
spectroscopy and differential pulse voltammetry were utilized for the characterization of the imprinted polymer film.
Results:
Under the optimized experimental conditions, the proposed sensor exhibited two distinct linear responses ranging
from 0.02 to 0.8 μmol L-1 and 0.8 to 10 μmol L-1 towards the concentrations of FA, and the detection limit was found to
be 2.8 nmol L-1 (S/N=3). The molecularly imprinted film proposed was also found to exhibit comparatively high
selectivity toward folic acid against structurally similar analogues, and the preparation of the sensor was simple and
reproducible.
Conclusions:
In this work, a molecularly imprinted film fabricated on a rGO-AuNPs modified electrode was developed
for the sensitive and selective determination of FA. Furthermore, the method was applied to the detection of FA in infant
formula milk, multivitamin tablets and blood serum sample with satisfactory results.
Electrochemical Preparation of a Molecularly Imprinted Polypyrrole-modified Pencil Graphite Electrode for Determination of Ascorbic Acid